Reports link heat waves, deluges to climate change

Scientists are increasingly confident that the uptick in heat waves and heavier rainfall is linked to human-caused greenhouse-gas emissions, posing a heightened risk to the world’s population, according to two reports issued in the past week.

On Wednesday, the United Nations Intergovernmental Panel on Climate Change released a 594-page study suggesting that when it comes to weather observations since 1950, there has been a “change in some extremes,” which stem in part from global warming.

The report — from 220 authors in 62 countries — makes distinctions among weather phenomena. It shows there is “limited to medium evidence” that climate change has contributed to changes in flooding, for example, and there is “low confidence” that long-term hurricane trends over the past 40 years have been driven by the world’s growing carbon output…